To date, mobile terminal devices such as cellular phones have included antennas inside casings thereof or outside the casings. When an antenna is disposed on the outside of a casing, the antenna is connected to a circuit board accommodated in the casing using a feeder line.
FIG. 13 is a schematic perspective view illustrating a part of the structure inside a casing of a known mobile terminal device. FIG. 14 is a longitudinal sectional view illustrating a part of the casing illustrated in FIG. 13. A mobile terminal device illustrated in FIGS. 13 and 14 includes a casing 103 formed of a first case 101 and a second case 102 joined together and having a through-hole 104 formed in a sidewall 103a thereof. A circuit board 105 on which various electronic components are mounted is accommodated in the casing 103.
An antenna 106 is formed of a flexible cable such as a flexible printed circuit (FPC). A first end of the antenna 106 is connected to a connector 107 on the circuit board 105 inside the casing 103. A second end of the antenna 106 extends to the outside of the casing 103 through the through-hole 104, and is held by a predetermined holder 108.
An elastic waterproofing grommet 109 is integrated with the antenna 106 at a predetermined position. The through-hole 104 is watertightly sealed by the grommet 109. An outer cover 110 is attached to the outside of the casing 103 so as to prevent exposure of the antenna 106.
The antenna 106 of the mobile terminal device shown in FIGS. 13 and 14 is formed on the flexible cable. The mobile terminal device shown in FIGS. 13 and 14 uses parts such as the connector 107 on the circuit board 105 and the holder 108 for fixing the flexible cable.
Japanese Laid-Open Utility Model Publication No. 7-29945 describes a metallic telescopic antenna instead of an antenna formed on a flexible cable. In J Japanese Laid-Open Utility Model Publication No. 7-29945, the telescopic antenna disposed on the outside of a casing and a connecting terminal accommodated in the casing are connected to each other via a through-hole formed in the casing.
In Japanese Laid-Open Utility Model Publication No. 7-29945, the connecting terminal is attached to the inside of the casing, and a base end of the telescopic antenna is attached to the inside of the casing. The connecting terminal and the base end of the telescopic antenna are fastened together by a conductive screw member fitted into the through-hole from inside the casing.